Carvedilol, (±) 1-(9H-carbazol-4-yloxy)-3-[[2-(2-methoxyphenoxy)-ethyl]-amino]-2-propanol of structure I, is a combined alpha- and betalytic with vasodilating activity.

According to DE 2815926 (U.S. Pat. No. 4,503,067) Carvedilol is prepared by the reaction of 4-(oxirane-2-ylmethoxy)-9H-carbazole (II) with 2-(2-methoxyphenoxy)ethylamine (III).

By the method described, Carvedilol is prepared in low yields, moreover contaminated with the bis-derivative. This problem is solved by the method according to EP 918 055, in which 4-(oxirane-2-ylmethoxy)-9H-carbazole (II) is coupled with N-benzylated 2-(2-methoxyphenoxy)ethylamine; by this method creation of bis-derivative is minimized and the yield of Carvedilol is increased, but a disadvantage of this method is introducing of an additional step—hydrogenolytic removal of the protective benzyl group on a palladium catalyst.
Another method of decreasing the amount of the bis-derivative and thus increasing the yield of the product in the process of preparation of Carvedilol is described in WO 0200216, wherein an epoxide (II) reacts with an amine (III) in a solvent or without any solvent, the product being isolated after the reaction in the form of Carvedilol hydrochloride hydrate from the reaction mixture after adding water, ethylacetate and diluted hydrochloric acid.
All the abovementioned methods of preparation of Carvedilol use, as one of the starting materials, the amine base (III), or its N-benzylated derivative, which have low stability—they are subject to decomposition in contact with air and light. The abovementioned disadvantages are solved by the method of this invention.